1. Field of the Invention
The present invention relates to reservoirs having liquid level sensing devices for indicating when the liquid level in the reservoir falls below a predetermined minimum. For example, the reservoir may be a hydraulic brake fluid reservoir for an automobile, and the sensing device may be electrically connected to a circuit for generating an alarm signal when the liquid level falls below the predetermined minimum due to leakage.
2. Description of the Prior Art
Many reservoirs having proximity sensors are known, in which a float member floating on the surface of the hydraulic fluid has a magnet which activates a proximity switch when the liquid level falls below a predeterined level. The proximity switch is conventionally enclosed within a hollow tubular member attached to an upper wall of the reservoir tank which comprises upper and lower shells made of synthetic resin. Such reservoir construction is advantageous because there is no damage due to heat welding in the connection of the upper and lower shells because the tubular member is attached to the tank after the heat welding has been performed. However, there is a disadvantage with regard to an increase in the manufacturing cost due to attaching the tubular member to the tank.